Non-monotonic behavior of weak-polyelectrolytes adsorption on a cationic surface: A Monte Carlo simulation study

In this work, the weak polyelectrolyte (PE) adsorption on a strong cationic surface is studied with constant pH Monte Carlo simulations using coarse-grained model. When large number of PE chains added to system, adsorbed amount vs curve exhibits non-monotonic behavior, appearance maximum close intrinsic pKa0-value titratable groups. The apparent pKa-value shows non-trivial tendency depending pH-value and coverage degree. increasing pH-value, small anions that accompany are replaced by cations. For pH>pKa0+1, an evident charge reversion observed. These results explained analyzing interplay between attractive repulsion electrostatic interactions different components system (inter- intra-charged monomers chains, ions) their effects chain ionization.